ASoC: mediatek: mt8186: add AFE_DAC_CON0 to volatile register list

Mark AFE_DAC_CON0 as volatile since DSP firmware will access this
register too.

Signed-off-by: Chunxu Li <chunxu.li@mediatek.com>
Link: https://lore.kernel.org/r/20230110092623.13035-1-chunxu.li@mediatek.com


Signed-off-by: Mark Brown <broonie@kernel.org>